The invention relates to a fabric for the sheet forming section of a papermaking machine comprising a double-layer or multi-layer fabric of interwoven longitudinal and transverse threads and additional transverse threads floating on the paper supporting side.
Papermachine fabrics having additional transverse threads floating on the paper supporting side are disclosed in U.S. Pat. Nos. 4,182,381 and 4,281,688 and in European Patent Publication No. A-85 363. According to U.S. Pat. No. 4,182,381, the additional transverse threads are to reduce wear, especially in the region of a loop seam. According to U.S. Pat. No. 4,281,688 the transverse threads are so interwoven that on the paper supporting side and on the running side, there are floats of equal length, which is to counteract curling of the edges.
According to European Patent Publication No. A-85 363, the additional transverse threads floating on the paper supporting side are to improve the removal of the sheet and increase the permeability. The additional transverse threads are so interwoven that they are crimped as little as possible. However, this makes them project on the paper supporting side so far that they interfere with sheet forming. When the fabric is cleaned by high pressure water jets, the projecting threads are frequently destroyed.